In recent years, diagnoses of health and constitutional predisposition of individual persons and foreseeing of illnesses have been increasingly enabled by inspections of genes and proteins of individual persons. As apparatuses for use therewith, there have been suggested various types of apparatuses, as will be described later. However, presently, these apparatuses have large sizes and are expensive and, in order to increase the processing efficiency for enabling performing a plurality of inspections at one time or in order to increase the determination accuracy, it has been necessary to increase the sizes of these apparatuses and to make these apparatuses more expensive. On the other hand, in order to cause these inspection apparatuses to be widely used, there has been a need for providing inexpensive apparatuses with reduced sizes and higher accuracy in the future.
Hereinafter, conventional apparatuses will be briefly described from the aforementioned perspective.
Japanese Unexamined Patent Publication Application No. 2000-131237 (Patent Document 1) suggests a fluorescence-detection type inspection apparatus. This is an apparatus for, after biomolecules are decorated with a fluorescent coloring agent, observing fluorescence emitted from the biomolecules which have specifically combined with cDNAs fixed on a slide glass. Such fluorescence-detection type inspection apparatuses enable performing analyses of a plurality of types of genes and proteins by applying different cDNAs to a slide glass in dot shapes. Accordingly, presently, such fluorescence-detection type inspection apparatuses have been widely used.
However, such inspection apparatuses induce the problem of the occurrence of errors due to fluorescent coloring agents, since they detect imperceptible fluorescence, and also induce the problem of large sizes of optical systems for fluorescence detection and, therefore, high fabrication costs.
Further, Japanese Patent Application Laid-Open Publication No. 6-167443 (Patent Document 2) suggests a bulk-type surface plasmon resonance sensor. This apparatus includes a triangular prism placed on the lower surface of a substrate, and a metal thin film formed on the upper surface of the substrate. The surface plasmon resonance sensor introduces light to the interface between the metal thin film and the prism at various angles, with a light projection optical system, and determines, with a photo detector, the intensity of the light reflected by the interface between the metal thin film and the prism. With this apparatus, it is possible to detect reactions between antibodies and the like fixed to the metal thin film and antigens which specifically combine therewith, from the change of the intensity of light received by the photo detector.
Such a bulk-type surface plasmon resonance sensor induces no error due to fluorescent molecules, but its structure is difficult to array and, accordingly, only a single inspection can be performed at one time with a single surface plasmon resonance sensor. Furthermore, conventional bulk-type surface plasmon resonance sensors have involved image processing for analyses, which has caused the surface plasmon resonance sensors to have large sizes and also has required times for analyses.
As means for reducing the sizes of surface plasmon resonance sensors, there have been suggested various types of optical-waveguide type surface plasmon resonance sensors which utilize waveguide-type surface plasmon resonance. An optical-waveguide type surface plasmon resonance sensor includes a core embedded in a clad layer and a metal thin film provided on the upper surface of the core, such that light is introduced to the core from its one end and the light emitted from the other end of the core is received by a photo detector.
JP-A. No. 2002-162346 (Patent Document 3) discloses such optical-waveguide type surface plasmon resonance sensors. This Document describes a structure having a single core and a structure having a plurality of cores formed in parallel by branching a core and providing a switching portion on the core. The structure having a single core enables providing only a single metal thin film therein, which makes it impossible to perform a plurality of inspections at one time.
Further, the structure having the plurality of cores enables providing metal thin films on the respective cores for performing a plurality of inspections at one time, but only a single core can be provided on each core. Accordingly, the number of metal thin films can not be made greater than the number of cores, and it is necessary to increase the number of cores and the number of switching portions, in order to increase the number of metal thin films. Furthermore, in order to branch the core in a plurality of stages, it is necessary to increase the area of the branched portion of the core, thereby increasing the size of the surface plasmon resonance sensor. Accordingly, such a surface plasmon resonance sensor having a plurality of cores has had the problem of the necessity of significantly increasing the size of the sensor in order to enable performing a plurality of inspections.
[Patent Document 1] JP-A. No. 2000-131237
[Patent Document 2] JP-A. No. 6-167443
[Patent Document 3] JP-A. No. 2002-162346